Sprint has upped its stake in Clearwire to 50.8 percent, and now has voting control over the company. The move comes shortly after Japanese carrier SoftBank agreed to purchase Sprint. America's third-largest carrier had a controlling share in Clearwire until earlier this year, when fears that its mounting debts would become a burden on the company prompted Sprint to sell off some of its shares. The move was reportedly a condition of SoftBank's takeover, as the Japanese carrier wanted full control over Clearwire's "vast reserves of spectrum."